Intermediate
30 min

Explore your favorite melodies with Si4731 and PIC18F57Q43

From AM's soulful beats to FM's vibrant tunes

AM/FM Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

AM/FM Click

Dev.Board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Immerse yourself in a symphony of sound as our radio receiver opens up the airwaves, bringing the rich tapestry of AM and FM music directly to your ears

A

A

Hardware Overview

How does it work?

AM/FM Click is based on the Si4731, a digital CMOS AM/FM radio receiver IC that integrates the complete broadcast tuner and receiver function from antenna input to digital audio output from Silicon Labs. The audio signal from the output of the Si4731 is brought to a mini 3.5 female jack on board over the LM4910 - an output capacitor-less stereo 35mW headphone amplifier from Texas Instruments. That way, it is ensured that the user can plug in the headphones directly into the Click board™ without the need for any external amplifier. The Si4731 IC The device leverages the Silicon Labs broadcast-proven digital low-IF architecture, enabling a cost-effective digital audio platform for consumer electronic applications with high TDMA noise immunity, superior radio performance, and high fidelity audio power amplification. The audio signal is processed to

have the optimal dynamic qualities. The integrated DSP also handles the signal's stereo MPX encoding and FM modulation. The low-level digital intermediate frequency (IF) signal is filtered out and sent to the outputs, amplified, filtered, and digitized with high-resolution analog-to-digital converters (ADCs). This advanced architecture allows the Si4731- to perform channel selection, FM demodulation, and stereo audio processing to achieve superior performance compared to traditional analog architectures. The Click is designed for communication over the I2C/2-wire control interface. When selecting 2-wire mode, the SCLK pin should stay at a HIGH logic level during the rising edge on the RST pin and stay HIGH until after the first start condition. Also, a start condition must not occur within 300nS before the rising edge on the RST pin. The 2-wire

bus mode uses only the SCL and SDA pins for communication. The Si4731 IC has the capability of the received signal measurement. The antenna used to broadcast the signal can also be used to accept the incoming signal sent by the receiving device. Although it can be used both to receive and transmit signals, the antenna can't operate in both modes simultaneously. This feature can be useful when calibrating the transmission power of the click board. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

AM/FM Click hardware overview image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

These standard small stereo earphones offer a high-quality listening experience with their top-notch stereo cable and connector. Designed for universal compatibility, they effortlessly connect to all MIKROE mikromedia and multimedia boards, making them an ideal choice for your electronic projects. With a rated power of 100mW, the earphones provide crisp audio across a broad frequency range from 20Hz to 20kHz. They boast a sensitivity of 100 ± 5dB and an impedance of 32Ω ± 15%, ensuring optimal sound quality. The Φ15mm speaker delivers clear and immersive audio. Cost-effective and versatile, these earphones are perfect for testing your prototype devices, offering an affordable and reliable audio solution to complement your projects.

AM/FM Click accessories image

Used MCU Pins

mikroBUS™ mapper

General-Purpose Output 1
PA0
AN
Reset
PA7
RST
I2C Address Selection
PD4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Shutdown
PB0
PWM
General-Purpose Output 2
PA6
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB1
SCL
I2C Data
PB2
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

AM/FM Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Curiosity Nano with PICXXX Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
PIC18F57Q43 Curiosity MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for AM/FM Click driver.

Key functions:

  • amfm_tune_up - This function increments current frequency for 10 KHz

  • amfm_set_volume - This function sets volume level in range: 0 - 63

  • amfm_get_stc -This function checks STC bit state

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \file 
 * \brief AmFm Click example
 * 
 * # Description
 * This app simulate RADIO RECEIVER.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes device.
 * 
 * ## Application Task  
 * Several additional functions are executed and printed over the terminal.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "amfm.h"

// ------------------------------------------------------------------ VARIABLES

static amfm_t amfm;
static log_t logger;

float aux;
uint8_t volume = 0x3F;
uint8_t mute_flag = 0;
uint8_t status;
uint16_t station_1 = 0;
uint16_t station_2 = 0;
uint16_t station_3 = 0;
uint16_t station_4 = 0;
uint16_t station_5 = 0;
uint16_t station_frequency = 0;
uint8_t memory = 0;

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

void amfm_case_memorize ( )
{
    switch ( memory )
    {
        case 0 :
        {
            station_1 = station_frequency;
            memory += 1;
            log_printf( &logger, "> > > station 1 memorized\r\n" );
            break;
        }
        case 1 :
        {
            station_2 = station_frequency;
            memory += 1;
            log_printf( &logger, "> > > station 2 memorized\r\n" );
            break;
        }
        case 2 :
        {
            station_3 = station_frequency;
            memory += 1;
            log_printf( &logger, "> > > station 3 memorized\r\n" );
            break;
        }
        case 3 :
        {
            station_4 = station_frequency;
            memory += 1;
            log_printf( &logger, "> > > station 4 memorized\r\n" );
            break;
        }
        case 4 :
        {
            station_5 = station_frequency;
            memory = 0;
            log_printf( &logger, "> > > station 5 memorized\r\n" );
            break;
        }
        default :
        {
            break;
        }
    }
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_station_1 ( amfm_t *ctx )
{
    log_printf( &logger, "> > > tune station 1 \r\n" );
    amfm_tune_frequency( ctx, station_1 );
    log_printf( &logger, "> > > tune done \r\n" );
    aux = station_1 / 100.0;
    log_printf( &logger, "> > > frequency: %f MHz \r\n", aux );
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_station_2 ( amfm_t *ctx )
{
    log_printf( &logger, "> > > tune station 2 \r\n" );
    amfm_tune_frequency( ctx, station_2 );
    log_printf( &logger, "> > > tune done \r\n" );
    aux = station_2 / 100.0;
    log_printf( &logger, "> > > frequency: %f MHz \r\n", aux );
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_station_3 ( amfm_t *ctx )
{
    log_printf( &logger, "> > > tune station 3 \r\n" );
    amfm_tune_frequency( ctx, station_3 );
    log_printf( &logger, "> > > tune done \r\n" );
    aux = station_3 / 100.0;
    log_printf( &logger, "> > > frequency: %f MHz \r\n", aux );
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_station_4 ( amfm_t *ctx )
{
    log_printf( &logger, "> > > tune station 4 \r\n" );
    amfm_tune_frequency( ctx, station_4 );
    log_printf( &logger, "> > > tune done \r\n" );
    aux = station_4 / 100.0;
    log_printf( &logger, "> > > frequency: %f MHz \r\n", aux );
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_station_5 ( amfm_t *ctx )
{
    log_printf( &logger, "> > > tune station 5 \r\n" );
    amfm_tune_frequency( ctx, station_5 );
    log_printf( &logger, "> > > tune done \r\n" );
    aux = station_5 / 100.0;
    log_printf( &logger, "> > > frequency: %f MHz \r\n", aux );
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_seek ( amfm_t *ctx )
{
    log_printf( &logger, "> > > seek \r\n" );
    amfm_seek( ctx );
    log_printf( &logger, "> > > seek done \r\n" );
    station_frequency =  amfm_get_channel( ctx );
    aux = station_frequency / 100.0;
    log_printf( &logger, "> > > frequency: %f MHz \r\n", aux );
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_plus ( amfm_t *ctx )
{
    if ( volume < 63 )
    {
        volume += 1;
        amfm_set_volume( ctx, volume );
        log_printf( &logger, "> > > volume: %u \r\n", volume );
    }
    else
    {
        log_printf( &logger, "> > > volume: MAX \r\n" );
    }
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_minus ( amfm_t *ctx )
{
    if ( volume > 0 )
    {
        volume -= 1;
        amfm_set_volume( ctx, volume );
        log_printf( &logger, "> > > volume: %u \r\n", volume );
    }
    else
    {
        log_printf( &logger, "> > > volume: MIN \r\n" );
    }
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_mute ( amfm_t *ctx )
{
    if ( mute_flag == 0 )
    {
        amfm_mute( ctx );
        log_printf( &logger, "> > > mute ON \r\n" );
        mute_flag = 1;
    }
    else
    {
        amfm_unmute( ctx );
        log_printf( &logger, "> > > mute OFF \r\n" );
        mute_flag = 0;
    }
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_tune_up ( amfm_t *ctx )
{
    amfm_tune_up( ctx );
    station_frequency = amfm_get_channel( ctx );
    aux = station_frequency / 100.0;
    log_printf( &logger, "> > > frequency: %f MHz \r\n", aux );
    log_printf( &logger, "-----------------------------------------\r\n" );
}

void amfm_case_tune_down ( amfm_t *ctx )
{
    amfm_tune_down( ctx );
    station_frequency = amfm_get_channel( ctx );
    aux = station_frequency / 100.0;
    log_printf( &logger, "> > > frequency: %f MHz \r\n", aux );
    log_printf( &logger, "-----------------------------------------\r\n" );
}

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    amfm_cfg_t cfg;

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, "---- Application Init ----" );

    //  Click initialization.

    amfm_cfg_setup( &cfg );
    AMFM_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    amfm_init( &amfm, &cfg );

    Delay_ms( 100 );
    status = amfm_init_device( &amfm );
    if ( status == 0 )
    {
        log_printf( &logger, "> > > app init done < < <\r\n" );
    }
    else if ( status == 1 )
    {
        log_printf( &logger, "> > >    timeout    < < <\r\n" );
    }
    
    amfm_case_seek( &amfm );
    amfm_case_memorize( );
    Delay_ms( 1000 );
    
    amfm_case_seek( &amfm );
    amfm_case_memorize( );
    Delay_ms( 1000 );
    
    amfm_case_seek( &amfm );
    amfm_case_memorize( );
    Delay_ms( 1000 );
    
    amfm_case_seek( &amfm );
    amfm_case_memorize( );
    Delay_ms( 1000 );
    
    amfm_case_seek( &amfm );
    amfm_case_memorize( );
    Delay_ms( 1000 );
    
    amfm_case_plus( &amfm );
    Delay_ms( 1000 );
}

void application_task ( void )
{
    amfm_case_station_1( &amfm );
    Delay_ms( 10000 );
       
    amfm_case_station_2( &amfm );
    Delay_ms( 10000 );
    
    amfm_case_station_3( &amfm );
    Delay_ms( 10000 );
    
    amfm_case_station_4( &amfm );
    Delay_ms( 10000 );
    
    amfm_case_station_5( &amfm );
    Delay_ms( 10000 );
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}

// ------------------------------------------------------------------------ END

Additional Support

Resources